The present disclosure relates to a toner conveying device for conveying, to a developing device, toner supplied from a toner case, and to an image forming apparatus including the toner conveying device, and specifically to a mechanism for opening and closing a toner supply opening through which the toner is supplied to the developing device.
A developing device is installed in an image forming apparatus which is a copier, a printer or the like that forms an image on a print sheet based on the electrophotography. Inside the developing device, developer including toner is stored. The developing device develops, with the toner included in the developer, an electrostatic latent image that has been formed on an image carrier such as a photoconductor drum. As developing is performed by the developing device, the toner inside the developing device is reduced. As a result, a toner case storing the toner is attached to the image forming apparatus such that the toner is supplied from the toner case to the developing device. Conventionally, the image forming apparatus is provided with a toner supply opening and an opening/closing member (shutter member), wherein the toner supply opening is used to supply the toner to the developing device, and the opening/closing member opens and closes the toner supply opening. The opening/closing member is coupled with an operation portion, such as an operation lever, provided on the toner case such that the user operates the operation portion to open and close the toner supply opening.
Meanwhile, when the toner case is attached to the image forming apparatus and an attempt is made to supply the toner in the state where the toner supply opening is closed by the opening/closing member, a toner supply passage connecting a toner discharge outlet of the toner case to the toner supply opening may be clogged with the toner and the toner may be aggregated. When the toner is aggregated, the opening/closing member may not be operated or may be broken. In addition, the aggregation of the toner may deteriorate the developability and decrease the image quality. As a result, in a conventional image forming apparatus, the operation portion is provided in an attachment portion to which the toner case is to be attached, and the operation portion is configured to interfere with a toner case when an attempt is made to attach the toner case in the state where the toner supply opening is closed, to prevent the toner case from being attached to the attachment portion in that state.